This invention relates to couplers for attaching excavator buckets and other tools to heavy construction equipment.
Quick couplers have been widely used with excavating equipment, e.g. hydraulic excavators (backhoes), to allow an individual piece of equipment to be used with a variety of tools, e.g., different buckets, grapples and the like, without extended downtime for changing tools. Conventional quick couplers are described in, e.g., U.S. Pat. Nos. 4,726,731 and 3,231,116. Quick couplers typically consist of a pair of spaced parallel plates, the plates defining holes for fixed attachment of the coupler to the end of a backhoe. The plates also define a first slot facing generally forward to engage a first pin on the bucket or tool, and a second slot, facing generally downward (disposed at 90.degree. to the first slot) to engage a second pin on the bucket or tool. In operation, the first pin is engaged in the first slot. The coupler is then rotated about the longitudinal axis of the first pin to engage the second pin in the second slot. The coupler and tool are thereafter secured together by engagement of a coupler gate with the second pin. This coupler gate is typically pivotally mounted to a pin on the coupler such that it pivots about a horizontal axis parallel to the longitudinal axes of the first and second slots/pins. These conventional couplers can be rendered virtually unusable by a relatively small degree of wear in the slots.